The invention relates to a screwing tool.
Screwing tools for components having a polygonal circumference are already generally known. These screwing tools can be open-ended spanners, ring spanners etc., which can also be used to screw cable glands with a heavy-gauge thread. These cable glands are used frequently in combination with electrical switch cabinets when it is a matter of making line connections to the inside or the outside. However, there is often a problem in that cable glands of this kind are very close together in switch cabinets, with the result that relatively strong open-ended spanners cannot be used since their arms cannot be inserted in the region between adjacent cable glands. Moreover, the open-ended spanners applied to the cable glands have to be removed and reapplied after only a small angle of rotation. This is relatively troublesome. Ring spanners cannot be used for the stated purpose of securing cable glands on the switch cabinet or removing cable glands from the switch cabinet since generally cables have been passed through the cable glands, and a ring spanner can therefore not be applied to the cable gland, that is to say to the hexagon belonging to the cable gland. The same applies to conventional ratchet spanners. The cable which is usually present prevents them from being applied to the cable gland too.
The object on which the invention is based is to make available a screwing tool for components which have a polygonal circumference that requires only a small amount of space to actuate the components and can also be used when material in the form of a strand has been passed through the component to be screwed. At the same time, it should be possible to carry out the screwing operation completely without having to reposition the screwing tool on the component after only a short angle of rotation.
A screwing tool according to the invention comprises: a handle; a clamping hoop, which is mounted pivotably on the handle at one end and is bent in the form of a partial circle at its other end, that remote from the handle; a stop for the clamping hoop, which is secured on the handle on the concave side of the clamping hoop; a return device on the handle, which device presses the clamping hoop against the stop; and an actuating member, which is held by the handle and the free end of which lies opposite to and at a distance from the concave side of that end of the clamping hoop which is bent in the form of a partial circle.
A screwing tool of this kind allows screwing of even very closely adjacent elements to be screwed since the clamping hoop can be made very thin, particularly in its region bent in the form of a partial circle, and this also applies to the actuating member held by the handle. Since there is furthermore always a gap between the free end of the actuating member and that end of the clamping hoop which is bent in the form of a partial circle, the screwing tool can also be applied easily to elements to be screwed, through which material in the form of a strand passes along the screwing axis of the said elements. Moreover, the return device means that the clamping hoop can yield, thus allowing the screwing tool to be operated in the manner of a ratchet in order in this way to be able to carry out a complete screwing operation which does not require the screwing tool to be repeatedly applied to the element to be screwed.
By means of the screwing tool according to the invention, it is possible, in particular, to considerably simplify the screwing operation in the case of cable glands with heavy-gauge threads on electrical switch cabinets since these cable glands are often extremely inaccessible and are furthermore positioned very close together.
According to an advantageous refinement of the invention, the clamping hoop has in the region of its end bent in the form of a partial circle, on its concave or inner side, driver projections spaced apart in the circumferential direction, which ensure that a component with a polygonal circumference is taken along better while being screwed rather than leaving this task solely to the free end of the actuating member. Torques can therefore be transmitted better to the element to be screwed.
According to another refinement of the invention, starting from the free end of the clamping hoop bent in the form of a partial circle, the driver projections are constructed in such a way, in the circumferential direction of the said hoop, that they first of all rise slowly, more specifically in the direction of the centre of the partial circle, and then fall suddenly. This thus results in a kind of sawtooth. The steep flank of the sawtooth points away from the free end of that end of the clamping hoop which is bent in the form of a partial circle. This gives a good driving effect on the element to be screwed when the screwing tool is moved in the screwing direction while, when the screwing tool is moved in the opposite direction, the gently rising flanks of the driver projections can slide over the edges of the element to be screwed more easily when the clamping hoop is deflected. This facilitates ratchet operation.
The clamping hoop and, with it, its bent end and the actuating member preferably lie in one and the same working plane. As a result the force can be transmitted more evenly to the element to be screwed. In addition, however, the handle can also extend in this working plane, leading to a very compact screwing tool.
A compression spring arranged between the convex side of the clamping hoop and the handle can preferably be used as the return device, leading to a relatively economical construction of the screwing tool.
In this arrangement, the handle can be in the form of a housing in order to accommodate the rotatably mounted end of the clamping hoop, the rear end of the actuating member and its direction of displacement, the stop and the return device. For example, the handle in the form of a housing may be capable of being divided parallel to the working plane and comprise a trough-shaped first part and a second part in the form of a cover.
According to yet another refinement of the invention, the handle can also have a chamber for the purpose of accommodating a second clamping hoop, the chamber being situated, for example, in the trough-shaped first part. The clamping hoop stored here can be thought of as a replacement for the clamping hoop already attached to the front of the handle, or the clamping hoop mounted by way of storage in the housing can be one with a different opening range.
In yet another refinement of the invention, the actuating member is mounted displaceably to allow adjustment of the distance between its free end and that end of the clamping hoop which is bent in the form of a partial circle, thereby making it possible to screw elements of different sizes as well, that is to say, for example, elements which have a different opening width. For this purpose, the free end of the actuating member is moved towards or away from the free end of the clamping hoop.
At the same time, there can be a device for locking the displacement position of the actuating member on the handle, making it easier to position and, of course, fix in the desired position.
For example, the locking device can have projections arranged on the actuating member or on an element which displaces the actuating member, the projections latching into recesses on the inner side of the handle.
However, it is also possible to provide a locking device which has a pawl, the pawl being mounted pivotably on the handle and one end of it being latchable to the actuating member. For this purpose, the actuating member can, for example, have a suitably designed row of teeth or other structures. The pawl can preferably be pivoted into the locking position by means of spring force by means of its other end, which projects from the handle. Reliable locking of the actuating member is thus achieved. It can be cancelled by pivoting this projecting end manually against the spring force.
To avoid unintentional actuation of the locking device or pawl, beads situated to the side of it, on the outside of the handle, can be provided.
Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.